1. Field of the Invention
The present invention relates to a developer container that contains developer to be used for image formation, a cartridge, which includes the developer container and is attachable to and detachable from an image forming apparatus, and an image forming apparatus that includes the cartridge.
Here, examples of the “image forming apparatus” include an electrophotographic copy machine, an electrophotographic printer (e.g., a light emitting diode (LED) printer, a laser beam printer), and an electrophotographic facsimile apparatus that form an image on a recording medium by using an electrophotographic image forming process.
Further, the term “cartridge” refers to a unit in which at least a developer container and a developer bearing member are integrally configured, and is attachable to and detachable from an image forming apparatus main body, or a unit in which a developer container, a developer bearing member, and at least an image bearing member are integrally configured, and is attachable to and detachable from an image forming apparatus main body.
Still further, the developer container is housed in the image forming apparatus or the cartridge.
2. Description of the Related Art
Conventionally, as discussed in Japanese Patent Application Laid-Open No. 2002-196585, inside a container that contains developer, which is attachable to and detachable from an image forming apparatus, an agitation conveyance member that conveys developer contained therein toward a developing roller while agitating the developer is provided. In the configuration discussed in Japanese Patent Application Laid-Open No. 2002-196585, a plurality of the agitation conveyance members are used.
Further, as a means for detecting the quantity of developer conveyed in the developer container, as discussed in Japanese Patent Application Laid-Open No. 2-197881, electrodes are provided on an agitation conveyance member that rotates and another part, a value of an electric signal based on an electrostatic capacitance between the electrodes is detected, whereby the quantity of developer is detected. Other configurations have been discussed also in Japanese Patent Application Laid-Open No. 11-174804, and Japanese Patent Application Laid-Open No. 2006-58756.
In the above-described configuration in which developer is conveyed as discussed in Japanese Patent Application Laid-Open No. 2002-196585, however, the agitation conveyance member can convey only the developer located within the rotation radius, and hence, the bottom surface of the container needs to be formed in an arc shape in a cross sectional view. Therefore, a projected portion needs to be formed in a region of a floor surface of the container which the agitation conveyance member cannot reach, so that the developer does not stay in the region of the projected portion. Therefore, this projected portion in the container becomes a dead space.
Further, in the configuration discussed in Japanese Patent Application Laid-Open No. 2-197881, in which the quantity of developer is detected, an electric signal that changes in accordance with the rotation action of the agitation conveyance member is detected. Therefore, the electric signal significantly varies with the presence state of the developer, which causes the detection result to vary significantly.